Jacketed press roll

ABSTRACT

A press roll assembly including a fabric sleeve shrunken tightly around the periphery and retained between the ends of the shell of the roll. The roll at its axial extremities has tapered peripheral zones to aid in maintaining sleeve tension and position.

United States Patent 1 1 1 Krake 1 Jan. 16, 1973- 541, JACKETED PRESS ROLL 2,997,406 8/1961 Freeman et all ..29 131 x 3,318,233 5/1967 Curtis ..29/1l9 X [75] Inventor Kenneth Krake 3,435,500 4/1969 Aser et al. ..29/130 [73] Assignee: Kimberly-Clark Corporation, 3,447,451 6/1969 ;Meskanen ..29/l21 N h Wi 3,468,242 9/1969 Schaffrath ..lOO/l2l [22] Filed: Sept. 3, 1970 FOREIGN PATENTS OR APPLICATIONS [211 App]. No.: 69,279 160,772 3 1933 Switzerland "29/119 Prima Examiner-Alfred R. Guest 1 52 us. 1. i51i 1m. "13211) 3 1 /31 1 Hemck 58 Field of Search....29/131, 130, 119, 122, 116 R; and Raymmd l [57] ABSTRACT References Cited A press roll assembly including a fabric sleeve shrunken tightly around the periphery and retained between UNITED STATES PATENTS the ends of the shell of the roll. The roll at its axial ex- 2,022,170 11/1935 Yeager ..29/131 X tremities has ta ered eriphera] zones to aid in main- P P 1,522,056 1/1925 Han "29/119 X taining sleeve tension and position. 1,775,392 9/1930 Gray .29/119 X 2,723,931 11/1955 Mercer ..29/130 X 4 Claims, 4 Drawing Figures .PATENTEDJAH 16 I875 3.710.470

SHEET 1 [IF 3 FIG.

FIG

PATENTEDJAHIBISYS snmanrs JACKETED PRESS ROLL BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to the art of papermaking. It is particularly concerned with a structure of a press roll useful in dewatering presses of paper machines. Still more specifically, the invention is concerned with a press roll assembly in which the shell of the press roll is provided with a fabric sleeve of shrinkable fibers.

2. The Invention With Relation to the Prior Art It is known in the papermaking art to provide a press roll with a fabric sleeve shrunken tightly around the periphery of the shell of the roll and retained by the shell ends. The sleeve comprises shrinkable synthetic fibers interwoven in a mesh fabric. The fibers are commonly monofilaments which, as fillers of the fabric, extend axially of the shell and as warp threads extend peripherally of the shell. The interwoven filaments define in the fabric small capillaries or pores which readily receive liquid. Accordingly, the use of a shell covered with such a sleeve in a dewatering press presents to a traveling paper machine felt or paper web a surface which readily extracts water from the felt or web, thus aiding dewatering of the felt or paper web.

Such an arrangement of shell and fabric sleeve is No. 3,318,233 issued May 9,

' the extent necessary to achieve the shrink function.

I have found that in many instancesthelife of a fabric shrink sleeve is distinctly limited. A number of factors apparently tend to reduce the operating life of the shrink. sleeve fabrics. A first difficulty is that of maintaining adequate tension in the fabric on the shell. A second difficulty, and one which is particularly pertinent at high speeds, is the attaining of a smooth peripheral surface of the tensioned fabric sleeve. The sleeve fabric should be such that lumps or imperfections of the fabric, including overlaps, are eliminated to prevent unbalance and provide for overall concentricity of the outer surface of the fabric. These and other difficulties may be minimized or overcome in accordance with this invention by, in effect, providing an integrity of structure in the roll assembly which enables it to have and retain an adequate shape during operation.

In more specific aspect the shrinkable fabric sleeve, as in the prior art, .is shrunken tightly around the periphery of the shell of the roll and is retained between axial ends of the shell. The fabric has filaments which extend generally axially and are in tension; the fabric also has other filaments 1 which extend peripherally of the shell and are also in tension. One factor tending to provide for short service life is the tendency of adjacent peripherally extending filaments peripherally extending filaments causes workingof the filaments, leading to their breakage and shortened fabric life. I have found that, by providing the axial ex tremities of the shell with tapered peripheral zones which so accommodate the fabric sleeve that the diameters of the shell and sleeve in such zones decreases toward the shell ends, the tendency toward filament movement is largely overcome. In effect, by

to roll on each other, permitting a looseness to develop BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood by reference to the following detailed description and accompanying drawings wherein:

FIG. 1 is a perspective view of a jacketed suction roll in accordance with the invention;

FIG. 2 is a fragmentary view in section much enlarged illustrating an end portion of the suction roll of FIG. 1; 1

FIG. 3 is a perspective view partially in section with parts broken away much enlarged further illustrating the arrangement of an end section of the roll of FIG. 1; and

drawing sheet with FIG 2 illustrating a principle of the invention.

Referring now to the drawings more in detail, the numeral l in FIG. 1 designates a jacketed suction roll. The roll (FIG. 2) has an outer shell 2 including a resilient cover 3 suitably of natural or synthetic rubber. Suction holes 4 extend-through the shell 2 and resilient cover 3. As illustrated in FIG. 2, the suction holes are wider at their outer ends, being tapered as they open toward the fabric 6. The taper 5 is not a necessary arrangement of the suction holes and some or all of the holes may be cylindrical, that is, the shape of a right circular cylinder, as indicated at 15 in FIG. 3. The jacket or cover 6 is itself suitably a conventional shrink sleeve and, as noted in the prior art, the fibers may be of nylon, a fiber made from one of a series of polyamide resins, a synthetic polyester such as dacron which is a fiber produced by the condensation of dimethyl terephthalate and ethylene glycol or.the dynel fibers made by copolymerization of .40 percent acrylonitrile and 60 percent vinyl chloride.

Frequently applied to both plain and suction presses throughout the paper industry, the fabric sleeve is a shrinkable fabric which is preferably woven endless commonly from percent of the synthetic monofilament yarns. The sleeve is manufactured slightly larger in diameter than the shell to which it is applied so that it is loose enough to slide on over the shell length. Yet the sleeve is sufficiently tight that it may be shrunk snugly onto the shell to provide propertensioning in the sleeve. The sleeve, of course, as illustrated in FIGQZ, is

woven longer than the face width of the roll so that there is adequate length for fastening of the ends.

FIG. 4 is a fragmentary and schematic view on the In the present instance the fabric 6 is drawn down tightly and shrunk onto the resilient cover 3. The cover 3 is itself tapered about the shell circumference as indicated at zone 7. The end of the resilient cover area, in effect, forms the conical shaped zone 7 tapered toward the shell end from the break line at about numeral 8. The lines 8 determine between them the operating surface which carries the wet web of paper or the like.

The structural arrangement as illustrated in FIG. 2 shows the angle of the cone as suitably between about and 12 and is dependent to some extent upon the specific character of the synthetic cover and the fabric of the sleeve. I have found that most suitably the cone angle, at a &J hardness P&J the cover of about 23-27 and with a high density polyester fabric sleeve, is about 7. As clearly indicated in FIG. 1, the opposite ends of the shell are similarly tapered. A P& J hardness range of l635 is generally useful depending upon the specific sleeve operating conditions and the like.

The fabric sleeve at each end terminates in a portion indicated at 9 which is retained between a smooth faced clamping ring 10 and a base ring 11. Cap screws 12 passing through the clamp ring 10 into the base ring 11 provide for such retention. As noted more clearly in FIG. 3, the plurality of cap screws 12 is provided about the periphery of theshell end. An annular end plate closes each end of the shell, and such is indicated at 13 in FIGS. 2 and 3. The plate is secured to the shell body 2 by a plurality of cap screws 14 which pass through the end plate 13 into the body 2. The base ring 11 is itself countersunk to receive the cap screws 14 which are flush mountedwith the surface of the base ring. I

As already noted, the shell in the zone 7 of the resilient cover3 is so tapered and the fabric cover so applied to the shell over the tapered end that each circumferential monofilament extending around the shell is at a different diameter than an adjacent monofilament. The purpose of this arrangement is to inhibit against shifting of the lengthwise extending monofilament shown at C at FIG. 4.

Referring more specifically to FIG. 4, it will be noted that the circumferential monofilaments D-2 through D-5 as positioned on the roll will be of successively lesser circumferential length. All of these monofilaments are of a lesser length than the circumferentially extending monofilaments D-l which lie adjacent the tapered portion of the end of the roll but on the portion of larger diameter. The effect of the different tensioning is to prevent a rolling of, for example, the filament D-S toward or over the filaments D-4, D-3, etc. and to thereby inhibit loosening of the axially extending monofilament C. In effect, the taper serves as a lock on the axially extending filaments of the jacket of the shell. I have found that this arrangement serves to materially increase the life of such jackets in operation both on plain and suction press rolls.

The sleeves themselves may suitably be applied in accordance with conventional practice. The shrink sleeve may normally be one-half to 1 percent larger than the maximum circumference of the roll. Specifically, the I sleeve then is passed over the shell in relatively loose fitting arrangement and with the ends 9 drawn down and secured between the rings 10 and 11. The sleeve,

. which is usually woven endless and is heat shrinkable, is

then heated to cause the shortening of the filaments both circumferentially and longitudinally. The heating may be by use of hot air guns or by rotating the roll in a For the purpose of receiving the cap screws, the heat shrinkable sleeve is pierced with a hot element such as a hot prong at areas 17. Additionally, the sleeve ends are slitted through as indicated at 16 and then overlapped to minimize or eliminate unwanted excessive gathering of the material on the shell ends.

The fabric sleeve in use has operated well at roll speeds of 5,000 fpm and at pressures of 500 pounds per lineal inch. The sleeves, and particularly those of polyester, appear to have but little adverse wear effect on cooperating felts in press nips. For optimum performance the sleeve is ground as already noted.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. A press roll assembly comprising a generally cylindrical shell and a fabric sleeve shrunken tightly around the periphery and retained between ends of said shell, said sleeve comprising shrinkable synthetic fibers interwoven in a mesh defining pores to absorb liquid therein, said mesh fabric having filaments in tension which extend axially of the shell and other filaments in tension which extend peripherally of the shell in close proximity to each other, said shell at its axial extremities having tapered peripheral zones accommodating the fabric sleeve so that the diameters of the shell and sleeve decrease toward the ends of the shell and the peripherally extending filaments in the tapered zones are of successively lesser circumferential length toward the shell ends and, in effect, lock the axially extending filaments against significant peripheral movement said shell including a resilient outer cover and said sleeve being non-adhe'sively attached to the cover.

2.-A roll assembly as claimed in claim 1 and in which the resilient outer cover of the shell has a- P&J plastometer of between about 16 and 35.

3. A roll assembly as claimed in claim 1 in which each tapered zone of the shell is a truncated cone and the angle of each cone is between about 5 and 12.

4. A roll assembly as claimed in claim 1 and in which the fabric sleeve is a polyester fabric and the resilient cover has a P&J'plastometer of between about 16 and 35. 

1. A press roll assembly comprising a generally cylindrical shell and a fabric sleeve shrunken tightly around the periphery and retained between ends of said shell, said sleeve comprising shrinkable synthetic fibers interwoven in a mesh defining pores to absorb liquid therein, said mesh fabric having filaments in tension which extend axially of the shell and other filaments in tension which extend peripherally of the shell in close proximity to each other, said shell at its axial extremities having tapered peripheral zones accommodating the fabric sleeve so that the diameters of the shell and sleeve decrease toward the ends of the shell and the peripherally extending filaments in the tapered zones are of successively lesser circumferential length toward the shell ends and, in effect, lock the axially extending filaments against significant peripheral movement said shell including a resilient outer cover and said sleeve being nonadhesively attached to the cover.
 2. A roll assembly as claimed in claim 1 and in which the resilient outer cover of the shell has a P&J plastometer of between about 16 and
 35. 3. A roll assembly as claimed in claim 1 in which each tapered zone of the shell is a truncated cone and the angle of each cone is between about 5* and 12*.
 4. A roll assembly as claimed in claim 1 and in which the fabric sleeve is a polyester fabric and the resilient cover has a P&J plastometer of between about 16 and
 35. 